Groups of tools can be deployed as a tool string into the wellbore of a well, such as an oil or gas well for extracting fluids that can include petroleum oil hydrocarbons from a subterranean formation. The tools of the tool string can be used to prepare the well for the production of petroleum oil hydrocarbons or other production fluids. The tools can include, for example, a packer assembly and electronic gauges that are relatively sensitive to shock loading. The tool string can also include a safety joint. The safety joint can allow one or more tools of the tool string to be removed from the wellbore. For example, perforating guns included in the tool string may become stuck following perforation of the tubing string of the well system. A safety joint can allow other tools of the tool string to be decoupled from the perforation guns and retrieved from the wellbore.
Safety joints can include a retention mechanism, such as a set of shear pins. The retention mechanism can prevent a mandrel of a safety joint from fully extending. Previous safety joints may include only a single retention mechanism. Safety joints including only a single retention mechanism can be prematurely released by, for example, a force caused by the firing of perforation guns shearing a set of shear pins. Prematurely releasing the retention mechanism can cause the safety joint to be actuated prematurely by partially or fully extending the mandrel during deployment of the tool string, thereby rendering the safety joint inoperable.
It is desirable to prevent premature actuation of a safety joint caused by the unintentional shearing of the shear pin assembly.